As hip replacement surgery becomes a more commonplace procedure in orthopedic medicine, there has been increasing focus on the design of the hip prostheses used. Due to the wide variation in bone structure from patient to patient and the wide array of clinical problems encountered, it is necessary to have prostheses of a number of different shapes and sizes. To address this problem, various modular designs comprised of two or more components have become popular. Use of such modular designs removes the need for keeping a vast inventory of one-piece hip prostheses and increases the options available to the surgeon during surgery.
Some previous two-piece modular hip prostheses have used wedges or sleeves which interconnect two parts of a prosthesis at the metaphyseal region. While such designs have provided an adequate connection for the modular prosthesis components, a medical risk exists to the recipient. The use of such sleeves and wedges inside the femoral canal raises the possibility of metal wear at the interface between the sleeve or wedge components from motion of the components relative to each other. Such metal wear may result in debris accumulating in the region of the patient's body containing the prosthesis, perhaps long after the surrounding bone has grown around it.